Communication units or other units that are capable of operating on a plurality of communication networks are becoming more common. There are situations where different communication networks that can provide service for the communication unit can have different dialing plans. For example, one network may require 10 digits for routing. Another network may be a local network, such as used in an enterprise, and may require only 3, 4, or 5 digits for routing within the network.
This can create problems or inconveniences for a user of a communication unit. For example, placing a call to an individual may require that a user know which of several communication networks is being utilized in order to provide a number that is compatible with the dialing plan for that network. This can result in excessive memory being used for phone books when multiple entries are needed for each associate. Techniques exist for appending, for example, an area code, but these techniques usually rely on operating within a given network, albeit a different portion of the network and do not address situations where diverse networks are available for service or situations where a dialed number is ambiguous. A need exists for improved methods and apparatus for reformatting dialed numbers.